While it's still bucketing down
Stay inside or under cover until the rain eases, and keep ladders away from the spouting in wind and rain. If water is getting close to light fittings, power points or the switchboard, turn the power off at the main switch if you can reach it safely. Keep everyone out of any room where the ceiling is sagging or bulging. If anyone is in danger, or the storm has opened up the roof and it isn't safe, call emergency services straight away.
What to do tonight
Catch it and clear the room
Buckets with a towel in the bottom, furniture and electronics moved, plastic over whatever won't shift. If it's coming in fast, our emergency roof leak guide covers the first hour.
Film the overflow
From a window or the shelter of the porch, film the spouting, valleys and downpipes at the heaviest point of the rain. Water sheeting over the back of the spouting, a valley spilling sideways or a downpipe that isn't flowing is the most useful thing a roofer can see, because none of it shows on a dry day.
Note the rain and the wind
Write down the time, roughly how heavy it was, and which way the wind was blowing. If it only leaks once the rain is hammering on the roof, say so.
Check the downpipes at ground level
A downpipe that's dry at the bottom while the spouting above overflows is blocked somewhere. If the outlet is at ground level and you can clear it by hand, go ahead. Leave anything higher for a roofer.
Book a roofer for the first dry day
Send your video. Ask them to start with the spouting, valleys and downpipes above the leak.
Why a downpour finds gaps that light rain doesn't
Spouting spilling over the back. When spouting is blocked, sagging or sits too high against the fascia, heavy rain can flow over the back edge instead of the front, run behind the fascia and end up in the eaves or ceiling.
Not enough downpipes. A long run of spouting draining to one downpipe, or a valley emptying far from any downpipe, is where overflow starts first.
Valleys and internal gutters. A valley takes water from two slopes at once and can spill sideways under the roofing when it's narrow or half blocked. An internal (box) gutter sits inside the roof line, so when it overflows there's nowhere for the water to go but in. Dimond says an overflow outlet at least the size of the main outlet should always be provided, and plenty of older internal gutters don't have one.
Wind behind the rain. New Zealand downpours often arrive with strong gusts that push water uphill under laps, ridge caps and flashings. If it only leaks in a southerly, or only in a nor'easter, that's the giveaway.
Flat and low-slope roofs. On Butynol and other membranes, a blocked outlet lets water pond until it finds a tired seam, which is why E2/AS1 expects membrane roofs to drain through an outlet with an overflow or a second outlet. Low-pitched iron roofs rely on their laps and underlay, and heavy, wind-driven rain can get past both.
Flat tiled roofs. Tiles shed water by slope. E2/AS1 sets minimum pitches, for example 15 degrees with underlay or 20 without for double profile concrete tiles, so an older, shallow tiled roof with nothing underneath has little defence when rain is driven up under the tiles.
The Building Code's external moisture clause, E2, requires roofs to shed rain and to stop water getting in that could cause undue dampness or damage. Plenty of roofs that coped for decades start to struggle once the spouting is half full of leaves or the valley has rusted thin.
What a New Zealand downpour can do
On 27 January 2023, Auckland's Albert Park recorded 280 mm of rain in under 24 hours, 211 mm of it in under 6 hours. NIWA called it at least a 1-in-200-year event, and it helped make that January Auckland's wettest month on record.
Short bursts do damage too. On 7 February 2005 a thunderstorm dropped 34 mm on Dunedin in 20 minutes, flooding houses, shops and streets. In December 2001, thunderstorms brought an estimated 100-year rainfall to the Napier and Hastings city centres, overwhelming stormwater drains and damaging roofs.
No spouting carries everything. What matters is that when it overflows, the water lands outside the house rather than inside it.
Fixes a roofer may suggest
- Clearing spouting, valleys and internal gutter outlets, and cutting back the trees that keep filling them
- Gutter guards where leaves or pine needles are the main culprit
- An overflow outlet or rainhead on an internal gutter, so excess water spills outside
- An extra downpipe, or one moved closer to a valley
- Bigger spouting where the existing run can't keep up with the roof area
- A wider or replacement valley, or a reworked Butynol outlet
- Re-hanging spouting with a proper fall so it drains instead of holding water
- A re-roof with new underlay where a tired, low-pitched roof keeps letting driven rain through
Will insurance cover a heavy-rain leak?
It depends on what caused it. The Insurance Council says house insurance is meant for sudden damage, which New Zealand courts treat as happening within minutes or hours, and its own example is a tree falling on the roof. Blocked gutters that overflow and damage the house are a different story: insurers don't treat that as sudden, so it generally isn't covered.
The Council describes an insurer declining a claim for water damage and rot from gutters left blocked with leaves for years. Keeping the spouting clear is far cheaper than finding out that way.
After a storm or flood, the Natural Hazards Commission covers your land only, and damage to the house itself goes through your private insurance. Our guides on insurance and roof leaks and storm damage claims go further.
Door-knockers after a big storm
- Someone turning up uninvited to fix your roof on the spot. Under the Fair Trading Act, a trader who arrives with an unsolicited quote doesn't count as invited.
- No written agreement. An uninvited direct sale (a deal done at your door that you didn't ask for) must be in writing and dated, and show the trader's name, street address, phone number and email, plus your right to cancel.
- Pressure to start today. You can cancel an uninvited direct sale within 5 working days of receiving your copy of the agreement, and the trader can't enforce it until that period is over.
- A big deposit up front. Consumer Protection advises paying no more than 10% if you're asked for a deposit at all.
- Cash only. If you do go ahead with a trader who approached you, Consumer Protection suggests paying by credit card so you can ask your bank for a chargeback if things go wrong.
Your part, and the roofer's
You can
- Filming overflow from a window or the porch in heavy rain
- Clearing downpipe outlets you can reach standing on the ground
- Booking a spouting clean before winter, or more often if you're under trees
- Noting the rain and wind each time it leaks
Leave to a roofer
- Clearing valleys and internal gutters, which means being on the roof
- Working out whether spouting and downpipes are big enough for the roof
- Fitting overflows, rainheads, extra downpipes or new spouting
- Checking laps, flashings and underlay on low-pitched roofs
What we'd do after the first downpour leak
Our first suspect would be drainage, not the roofing itself. We'd hand the roofer the video and ask them to check every spouting run, valley and downpipe on the wet side of the house before anything else. If clean spouting still overflowed, we'd want a price for more downpipe capacity or a proper overflow, because a second clean won't change how much water the system can carry.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.